/***************************************************************************/
/*                                                                         */
/*  ftcalc.h                                                               */
/*                                                                         */
/*    Arithmetic computations (specification).                             */
/*                                                                         */
/*  Copyright 1996-2001, 2002, 2003, 2004, 2005, 2006, 2008, 2009 by       */
/*  David Turner, Robert Wilhelm, and Werner Lemberg.                      */
/*                                                                         */
/*  This file is part of the FreeType project, and may only be used,       */
/*  modified, and distributed under the terms of the FreeType project      */
/*  license, LICENSE.TXT.  By continuing to use, modify, or distribute     */
/*  this file you indicate that you have read the license and              */
/*  understand and accept it fully.                                        */
/*                                                                         */
/***************************************************************************/


#ifndef __FTCALC_H__
#define __FTCALC_H__


#include <ft2build.h>
#include FT_FREETYPE_H


FT_BEGIN_HEADER


/*************************************************************************/
/*                                                                       */
/* <Function>                                                            */
/*    FT_FixedSqrt                                                       */
/*                                                                       */
/* <Description>                                                         */
/*    Computes the square root of a 16.16 fixed point value.             */
/*                                                                       */
/* <Input>                                                               */
/*    x :: The value to compute the root for.                            */
/*                                                                       */
/* <Return>                                                              */
/*    The result of `sqrt(x)'.                                           */
/*                                                                       */
/* <Note>                                                                */
/*    This function is not very fast.                                    */
/*                                                                       */
FT_BASE(FT_Int32)
FT_SqrtFixed(FT_Int32 x);


#ifdef FT_CONFIG_OPTION_OLD_INTERNALS

/*************************************************************************/
/*                                                                       */
/* <Function>                                                            */
/*    FT_Sqrt32                                                          */
/*                                                                       */
/* <Description>                                                         */
/*    Computes the square root of an Int32 integer (which will be        */
/*    handled as an unsigned long value).                                */
/*                                                                       */
/* <Input>                                                               */
/*    x :: The value to compute the root for.                            */
/*                                                                       */
/* <Return>                                                              */
/*    The result of `sqrt(x)'.                                           */
/*                                                                       */
FT_EXPORT(FT_Int32)
FT_Sqrt32(FT_Int32 x);

#endif /* FT_CONFIG_OPTION_OLD_INTERNALS */


/*************************************************************************/
/*                                                                       */
/* FT_MulDiv() and FT_MulFix() are declared in freetype.h.               */
/*                                                                       */
/*************************************************************************/


#ifdef TT_USE_BYTECODE_INTERPRETER

/*************************************************************************/
/*                                                                       */
/* <Function>                                                            */
/*    FT_MulDiv_No_Round                                                 */
/*                                                                       */
/* <Description>                                                         */
/*    A very simple function used to perform the computation `(a*b)/c'   */
/*    (without rounding) with maximal accuracy (it uses a 64-bit         */
/*    intermediate integer whenever necessary).                          */
/*                                                                       */
/*    This function isn't necessarily as fast as some processor specific */
/*    operations, but is at least completely portable.                   */
/*                                                                       */
/* <Input>                                                               */
/*    a :: The first multiplier.                                         */
/*    b :: The second multiplier.                                        */
/*    c :: The divisor.                                                  */
/*                                                                       */
/* <Return>                                                              */
/*    The result of `(a*b)/c'.  This function never traps when trying to */
/*    divide by zero; it simply returns `MaxInt' or `MinInt' depending   */
/*    on the signs of `a' and `b'.                                       */
/*                                                                       */
FT_BASE(FT_Long)
FT_MulDiv_No_Round(FT_Long a,
                   FT_Long b,
                   FT_Long c);

#endif /* TT_USE_BYTECODE_INTERPRETER */


/*
 *  A variant of FT_Matrix_Multiply which scales its result afterwards.
 *  The idea is that both `a' and `b' are scaled by factors of 10 so that
 *  the values are as precise as possible to get a correct result during
 *  the 64bit multiplication.  Let `sa' and `sb' be the scaling factors of
 *  `a' and `b', respectively, then the scaling factor of the result is
 *  `sa*sb'.
 */
FT_BASE(void)
FT_Matrix_Multiply_Scaled(const FT_Matrix * a,
                          FT_Matrix * b,
                          FT_Long scaling);


/*
 *  A variant of FT_Vector_Transform.  See comments for
 *  FT_Matrix_Multiply_Scaled.
 */

FT_BASE(void)
FT_Vector_Transform_Scaled(FT_Vector * vector,
                           const FT_Matrix * matrix,
                           FT_Long scaling);


/*
 *  Return -1, 0, or +1, depending on the orientation of a given corner.
 *  We use the Cartesian coordinate system, with positive vertical values
 *  going upwards.  The function returns +1 if the corner turns to the
 *  left, -1 to the right, and 0 for undecidable cases.
 */
FT_BASE(FT_Int)
ft_corner_orientation(FT_Pos in_x,
                      FT_Pos in_y,
                      FT_Pos out_x,
                      FT_Pos out_y);

/*
 *  Return TRUE if a corner is flat or nearly flat.  This is equivalent to
 *  saying that the angle difference between the `in' and `out' vectors is
 *  very small.
 */
FT_BASE(FT_Int)
ft_corner_is_flat(FT_Pos in_x,
                  FT_Pos in_y,
                  FT_Pos out_x,
                  FT_Pos out_y);


#define INT_TO_F26DOT6(x)    ((FT_Long)(x) << 6)
#define INT_TO_F2DOT14(x)    ((FT_Long)(x) << 14)
#define INT_TO_FIXED(x)      ((FT_Long)(x) << 16)
#define F2DOT14_TO_FIXED(x)  ((FT_Long)(x) << 2)
#define FLOAT_TO_FIXED(x)    ((FT_Long)(x * 65536.0))
#define FIXED_TO_INT(x)      (FT_RoundFix(x) >> 16)

#define ROUND_F26DOT6(x)     (x >= 0 ? (((x) + 32) & - 64) \
                              : (-((32 - (x)) & - 64)))


FT_END_HEADER

#endif /* __FTCALC_H__ */


/* END */